Design and Characterization of a 43.2-ps and PVT-Resilient TDC for Single-Photon Imaging Arrays

This brief describes the design and characterization of a ring oscillator-based time-to-digital converter (TDC) with down to 43.2 ps of time resolution and high tolerance to process, voltage and temperature variations. By employing a compact architecture, it is therefore suitable for inclusion in imaging arrays for time-stamping functions. The proposed TDC has been fabricated in a 0.13-μm CMOS technology in a 16 × 8 array of single-photon avalanche diode-based pixels for positron emission tomography applications and thoroughly characterized.